Time delay elements are used in a variety of analog circuits to cause analog signals to experience a time delay. In particular, time delay elements are important for RF transceivers, where they may be used for amplifier pre-distortion, feed-forward linearization, and active interference cancellation techniques. Of course, such time delay elements may find use in a wide variety of applications involving analog signal transmission, processing, and/or synthesis.
Unfortunately, traditional delay elements (e.g., ceramic filters, SAW filters, coaxial cables, waveguide cavity resonator-based filters) may limit the performance of analog circuits; in particular, RF transceivers, due to one or more of the following problems: excessive size, excessive cost, excessive complexity, poor manufacturability, high loss, or high amplitude ripple or high phase ripple.
Thus, there is a need in the field of analog circuits to create new and useful high quality factor time delay filters. This invention provides such new and useful filters.